FERMT2 Protein

FERMT2 Protein

Overview

FERMT2 protein (Fermitin Family Member 2, also known as Kindlin-2 or MIG-2) is a FERM domain-containing adaptor protein encoded by the [FERMT2](/genes/fermt2) gene. FERMT2/Kindlin-2 is an essential integrin co-activator that links integrins to the actin cytoskeleton and mediates cell adhesion, migration, and extracellular matrix signaling. FERMT2 is a genome-wide significant risk locus for [Alzheimer's disease](/diseases/alzheimers-disease), and emerging evidence implicates it in [amyloid precursor protein (APP)](/genes/app) trafficking, [amyloid-beta](/proteins/amyloid-beta) production, and [tau](/proteins/tau) pathology.

FERMT2 Protein

Overview

FERMT2 protein (Fermitin Family Member 2, also known as Kindlin-2 or MIG-2) is a FERM domain-containing adaptor protein encoded by the [FERMT2](/genes/fermt2) gene. FERMT2/Kindlin-2 is an essential integrin co-activator that links integrins to the actin cytoskeleton and mediates cell adhesion, migration, and extracellular matrix signaling. FERMT2 is a genome-wide significant risk locus for [Alzheimer's disease](/diseases/alzheimers-disease), and emerging evidence implicates it in [amyloid precursor protein (APP)](/genes/app) trafficking, [amyloid-beta](/proteins/amyloid-beta) production, and [tau](/proteins/tau) pathology.

<div class="infobox infobox-protein"> [@chapuis2013]
<div class="infobox-header">FERMT2 Protein</div> [@elosuabayes2024]
<table> [@kunkle2019]
<tr><td class="infobox-label">Protein Name</td><td>Fermitin family homolog 2 (Kindlin-2)</td></tr> [@ma2008]
<tr><td class="infobox-label">Gene</td><td>[FERMT2](/genes/fermt2)</td></tr>
<tr><td class="infobox-label">UniProt ID</td><td>[Q96AC1](https://www.uniprot.org/uniprot/Q96AC1)</td></tr>
<tr><td class="infobox-label">PDB IDs</td><td>[3VIH](https://www.rcsb.org/structure/3VIH)</td></tr>
<tr><td class="infobox-label">Molecular Weight</td><td>78.4 kDa</td></tr>
<tr><td class="infobox-label">Subcellular Localization</td><td>Focal adhesions, cytoplasm, cell membrane</td></tr>
<tr><td class="infobox-label">Protein Family</td><td>Kindlin/Fermitin family (FERM domain proteins)</td></tr>
<tr><td class="infobox-label">Associated Diseases</td><td>[Alzheimer's disease](/diseases/alzheimers-disease)</td></tr>
</table>
</div>

Structure

Domain Architecture

• F0 subdomain (residues 1-92): Ubiquitin-like fold; mediates membrane targeting
• F1 subdomain (residues 93-259): Contains an inserted pleckstrin homology (PH) domain for phosphoinositide binding (PI(3,4,5)P3 and PI(3,4)P2)
• F2 subdomain (residues 260-545): Structural core of the FERM domain
• F3 subdomain (residues 546-680): Contains the integrin β-tail binding site (NPxY motif recognition); directly binds integrin β1, β2, and β3 cytoplasmic tails

Integrin Activation Mechanism

Normal Function

Cell Adhesion and Migration

• Essential co-activator for integrin-mediated cell adhesion to extracellular matrix
• Required for focal adhesion assembly and maturation
• Connects integrins to the actin cytoskeleton through interactions with ILK, paxillin, and migfilin
• Knockout is embryonic lethal in mice (defective heart and vascular development)

Brain-Specific Functions

• Expressed in [neurons](/entities/neurons), [astrocytes](/cell-types/astrocytes), and [microglia](/cell-types/microglia)
• Neuronal FERMT2 regulates dendritic spine morphology through integrin signaling
• Supports synaptic adhesion and plasticity at excitatory synapses
• Modulates neuronal migration during development

APP Trafficking

• FERMT2 regulates [APP](/genes/app) endocytic trafficking through integrin-dependent endosomal sorting
• FERMT2 knockdown increases APP residence time in endosomes, promoting amyloidogenic processing
• FERMT2 modulates the interaction between APP and the retromer complex ([VPS35](/genes/vps35)/VPS26/VPS29)

Role in Disease

Alzheimer's Disease

• Risk variants reduce FERMT2 expression in the brain
• FERMT2 knockdown in neurons increases Aβ42 production by shifting APP processing toward the amyloidogenic pathway
• FERMT2 deficiency impairs APP recycling from endosomes to the cell surface
• FERMT2 also modulates [tau](/proteins/tau) phosphorylation through integrin-linked kinase (ILK) signaling
• Reduced FERMT2 expression correlates with faster cognitive decline in AD patients
• FERMT2 expression is reduced in AD [hippocampus](/brain-regions/hippocampus) and [entorhinal cortex](/brain-regions/entorhinal-cortex)

Mechanisms of AD Risk

Therapeutic Targeting

• FERMT2 is a potential therapeutic target for AD, but as a loss-of-function risk factor, restoration strategies are needed
• Gene therapy: AAV-FERMT2 delivery to restore expression in vulnerable brain regions
• Integrin signaling modulators: Small molecules that enhance integrin activation may compensate for FERMT2 reduction
• Retromer stabilizers: R33 and similar compounds may partially compensate for FERMT2-dependent APP trafficking defects

See Also

• [FERMT2 Gene](/genes/fermt2)
• [APP](/genes/app) — [amyloid precursor protein](/entities/app-protein)
• [BACE1](/genes/bace1) — [beta-secretase](/entities/bace1)
• [VPS35](/genes/vps35) — retromer complex
• [Amyloid Cascade Pathway](/mechanisms/amyloid-cascade)

External Links

• [UniProt: Q96AC1](https://www.uniprot.org/uniprot/Q96AC1)
• [PDB: 3VIH](https://www.rcsb.org/structure/3VIH)
• [GeneCards: FERMT2](https://www.genecards.org/cgi-bin/carddisp.pl?gene=FERMT2)

References